This present invention concerns an amphibious off-road vehicle, and more particularly such a vehicle having a left wheel-train and a right wheel-train arranged to propel the vehicle on both land and water, propulsion resources to drive the said wheel trains, and movable control resources capable of supplying a control signal as a function of their position.
We are already familiar with off-road vehicles, of the 4-wheel or 6-wheel type in particular, equipped with an internal-combustion engine driving the wheels through a transmission chain. On land, the manoeuvrability of the vehicle in order to drive it in a given direction is achieved by locking one of the wheel trains and driving the other in order to steer the vehicle in the required direction.
Off-road vehicles with internal-combustion engines have a certain number of drawbacks however.
In the first place, their manoeuvrability is not optimal.
In addition, since they are off-road vehicles, they are designed to be used essentially in a rural setting. But these vehicles are noisy, and they also give rise to atmospheric pollution by the emission of exhaust gases.
We are also familiar with off-road vehicles, of the 4-wheel or 6-wheel type in particular, equipped with an electric motor.
Document U.S. Pat. No. 5,842,532 describes a six-wheeled electric vehicle for the transportation of one person. This vehicle is fitted with a left wheel-train and a right wheel-train driven by propulsion resources. However control of the motors is not optimised so as to achieve satisfactory steering accuracy. Moreover, the vehicle described does not have characteristics that would allow optimal motion on water, on slippery land, or in soft, muddy or snow-covered landscapes.
In these particular applications, control of the motors is particularly critical due to the reduced resistance of the ground to the movements of the vehicle.